Electromagnetic motor device



p 9, 1967 E. F. c. scHuLzE 3,343,112

ELECTROMAGNETIC MOTCR DEVICE Filed May 24, 1966 INVENTOR. ERwm EC. SCHULZE ATTORNEY.

United States Patent 3,343,112 ELECTROMAGNETIC MOTOR DEVICE Erwin F. C. Schulze, Novelty, Ohio, assignor to Addressograph-Multigraph Corporation, Cleveland, Ohio, a corporation of Delaware Filed May 24, 1966, Ser. No. 552,455 Claims. (Cl. 335-254) ABSTRACT OF THE DISCLOSURE A device having opposed electromagnets employed to actuate a common armature in a manner which permits the armature to be magnetically influenced by the action of the electromagnetic coil operating to pull the armature in the opposite direction from which it resides at any particular time, wherein any residual magnetic orientation which may prevent rapid movement of a common armature, is forcibly reversed in order to remove vestiges of prior magnetic influence.

Related application The parent application, Ser. No. 368,005, was developed to drive a gate device which determines the path of travel of cards passing through a sorting device. Little actual power is needed, but exceptionally fast movement is required because hundreds of cards per minute pass along the table of the sorting device.

The electrical concept of the invention was also adapted into an improved structure as shown in related application Ser. No. 374,767, now issued as United States Patent No. 3,278,021. The problem here involved was one of adapting the electrical concepts of the parent application into a physical environment which would make impossible the use of the knife edge bearing as originally conceived in the parent application, now issued as United States Patent No. 3,272,498. In this related application, there is also need for rapid drive, but the drive is of a latching arm which actually is subject to a force from a catch shoulder of a device which imparts upon and presses down along the axis of the latch arm and hence places a considerable frictional force between the latch and the catch. Thus, in this situation, both power and speed are required.

Common to both of these situations is the requirement of speed. Speeds of 4 /2 to 5 milli-seconds are obtained with the drive devices of this invention. In obtaining these speeds, not only was it necessary to find a means for producing a quick power surge, but it was found that the prior art construction of electromagnetic power devices produce residual magnetism in actuated parts which actually produces a retarding effect on the desired ultimate action.

Description of the invention Under the above heading Abstract of the Invention is set forth the general object which is intended to be accomplished by the present invention, and further objects and a fuller understanding of this invention will be obtained by referring to the following specification in which:

FIGURE 1 is a side elevation of an opposed coil electromagnetic motor device operating a swinging latch of a catch device for apparatus as shown in application Ser. No. 374,767; and

FIGURE 2 is a side elevation of a modified form of the opposed coil electromagnetic motor device for light or no load control actuation, as used in apparatus of the type shown in application Ser. No. 368,005.

One problem encountered in the design of mechanisms for stay-open or stay-closed operation is that of obtaining a rapid action without getting into inordinately large and unwieldly activating mechanisms. Assuming that a mechanism is to be moved between two positions, using a return or closing spring for one direction of movement, then the action of that spring must be overcome. If the action is to be opposed to the spring as rapidly as possible, it can be appreciated that, as a result of the sum of these requirements, a very large electromagnetic coil is required. If the system is designed to handle a high voltage which Will operate the device rapidly notwithstanding the spring and the inductive reactance during current build up, it must then either have a coil designed to withstand the current heating effect due to the same voltage during the extended static hold-open condition, or else must have an additional circuitry for lowering the voltage after an initial high voltage opening pulse.

The present invention has for another object, therefore, the avoidance of these ditficulties and the provision of a stay-open, stay-closed operating mechanism which can produce an extremely rapid movement without an unwieldly activating mechanism.

The above stated object is directed to the specific use of the FIGURE 2 embodiment of the parent construction, and in order to avoid any misconcept that the invention is directed to the output structure, attention is therefore directed to the FIGURE 1 alternate embodiment which is not bi-stable, but rather is constantly urged in one direction in order to provide a safety feature. These two differ ent modes of output use are not to be confused with the electrical components of the present invention.

The bi-stable operation of FIGURE 2 is accomplished in accordance with the present invention by foregoing the return spring and employing two coils, one for moving mechanism in a first direction and one for moving it in the opposite direction. Both coils can be of minimal size because a very short high voltage pulse is needed to produce rapid movement in either direction, and beyond the short duration of this pulse, the activating means remains in a totally de-energizable state.

A feature of the present invention in one of its preferred forms is the arrangement of a leaf or armature, in driving relation with the driven device, which armature is acted upon by two electromagnets, one for movement in a first direction and one for movement in a second direction.

In the interest of high speed operation, which is the primary object of this invention, the holding frames for the opposed coils and various mounting parts are included in the iron circuit. Each embodiment illustrated also includes a common armature of iron which is part of a closed circuit. Then, it is a common magnetic feature of both embodiments that the coils are so wound that their flux paths through the common armature is such that the tendency of the armature to retain residual magnetism due to first coil action is forcibly overcome by the application of a strong magnetic force in the opposite direction, by second coil actuation.

Any magnetic material, having been oriented with a magnetic field and exposed to any degree of time or shock, will retain some of the applied magnetic influence. Hence, when an armature of magnetic material is positioned between two opposed magnets and one of the magnets actuated to draw the armature into contact with it, then that armature tends to stay in contact with the coil to which it has been drawn despite the cessation of electrical energy to the coil. Hence, energization of the opposing coil to draw the armature member away from its first position must first overcome the slowness of that member to change its magnetic orientation. Thus, some delay occurs simply in building up sufficient power to break whatever bonds exist, regardless of how weak that bond may be.

For convenience, refer first to the FIGURE 2. The

motor device, which may be conveniently referred to as an actuator, comprises a frame 31, a pair of electromagnets 33 and 35, mounted on the frame with their pole pieces 37 and 39 respectively directed towards each other and spaced apart a predetermined amount which can be adjusted by reason of the clamp screws 41 being slidable in slots 43. Note that the frame 31 is composed of a plurality of actual parts as dictated by manufacturing requirements and for the purpose of fitting the structure into an operating machine. However, the frame functions electrically as two opposed C-frames with corresponding legs of each of the opposed frames spaced to form an air gap, and the other legs joined together.

At the point on the frame 31 between the magnets 33 and 35, there is a groove 45 which receives an edge 47 formed at one end of an armature 49 of magnetic materials such as soft iron. This armature is arranged to extend between the pole pieces 37 and 39. The armature is designed to rock about its edge 47 and to have a few degrees of movement from one pole piece to the other. Holding the armature in a leftward position and into the groove 45 is a leaf spring 51. In the form shown, this is a spring of C-shape having small openings in its ends. One of these openings receives a pin 53 on the end of the armature 49, and the other seats on the point of a screw perch 55 mounted on arm 57 which is adjustable transversely of the groove 45 by reason of its mounting on frame 31 through clamp screws 59 and slots 61. The spring 51 is, of course, in a deflected condition when engaged with the armature and screw perch '55 and tends to expand and to exert an axial force along the armature 49. As such, it acts as a conventional overcenter spring and tends to snap the armature to one side or the other whenever it passes a centralized position.

The center point for the action of spring 51 can be positioned to accord with the mid-position for the armature 49 in the pole piece gap by shifting the support point for the outer spring end. This is accomplished by shifting arm 57 via its mounting screws 59.

The embodiment of FIGURE 2 is a fast action device, but the armature 49 is not capable of sustaining any appreciable load, other than a light retaining load such as of the spring 51, because the knife edge 47 acting in the groove 45 will wear too rapidly under loaded conditions. Nevertheless, this structure does provide a good contact for a low reluctance magnetic path.

The FIGURE 1 embodiment is a modification provided for the purpose of giving high speed action in situations where end loading of the armature is required. For example, the device illustrated in the FIGURE 1 is used in the parent application identified above wherein a shaft 71 is a torsion bar having a shoulder 72 acting as a stop to abut the end of an armature 100. In such operation the frictional contact between the end of the armature and the shoulder 72 is exceptionally high, and impact is intense. Nevertheless, torsion bar 71 used in a card sorting device for business machine use will require operation as high as five hundred cycles or more per minute and hence the operation of the armature 100 must be as fast as the operation of the non-loaded armature 49 shown in FIG- URE 2. Hence, it is essential to provide all energy toward accomplishing the end purpose, and to avoid the loss of power and time due to unintended residual magnetism.

The embodiment shown in FIGURE 1 is composed of a large C-shaped structure having the magnets opposed to one another across the gap in the structure. For practical manufacturing purposes, the device ise constructed around two separate C-sections. A first C-shaped magnetic core member 197 is mounted on suitable mounting means for operation. The upper end of the C-shaped core 197, which projects horizontally, carries a stop coil 194, the coil being disposed in encompassing relation to the cantilever portion of the core 197. The opposite side of the mechanism is of similar construction and includes a second C-shaped magnetic core member 198 mounted in opposite relationship to the core 197 to complete the major C-configuration. A coil is mounted on the upper horizontal projection portion of the core memher 198. The end of the core member 197 projects beyond the coil 194 and terminates in a pole piece 203. A similar pole piece 204 is formed on the end of the core member 198 projecting outwardly of the electromagnet 195. The pole pieces 203 and 204 are engageable with the high permeability armature 100, which constitutes a part of the operating mechanism. It is the latch for the catch in this particular analogy.

The pole pieces are integral parts of the cores, and the coils are locked on the cores to prevent the movement of the coils toward the pole piece ends. The armature 100 swings about a pivot center. The pole piece ends and the side faces of the armature are, therefore, formed to lie along a radius from the pivot center. The flux gap is caused to remain uniform over the full swing of the armature, because the radial lines will assure a uniform air gap.

Because the armature 100 is subject to extreme end blows, and to frictional drag whenever the latch is pulled out from under the shoulder 72, a structure is required which has strength. This dictates the use of alloy steel. However, alloy steel is not a suitable magnetic material for the electrical properties desired. Therefore, the FIG- URE 1 embodiment is constructed by making the armature 100 of two parts acting as an aggregate. A steel frame 205 is shaped somewhat in the form of an inverted U. In the FIGURE 1, which is a cross-section, the top cross bar of the U is shown in contact with the shoulder 72. This cross bar is hatched in the drawing because it is a section. The far leg of the inverted U is indicated by reference character 205A in the drawing, and this is not cross-hatched because it is a full side view lying behind the magnetic armature 100. The base of the leg 205A is journaled in a strong bearing, and the portion of the inverted U which is not illustrated is journaled in a similar hearing. The two bearings straddle the magnetic insert 100. A shaft 207 extends between the two journals and the magnetic insert 100 is loosely journaled upon that shaft 207. Additionally, the magnetic armature 100 is secured within the bridge of the inverted U frame 205 and, therefore, operates as an integral part with the frame. Actually, the magnetic drive is exerted upon the armature 100 which transfers the power through the connection to the structural member 205.

The magnetic armature 100 extends downwardly and terminates in a cylindrical hub portion 206. The hub portion 206 is disposed in longitudinal alignment between the opposed lower ends of the core members 197 and 198. The lower ends of the core members are given a configur-ation such that a minimum uniform air gap is afforded between each of the core members and the magnetic armature 100. Close configuration for the purpose of providing a minimum air gap is highly desirable, because any air gap produces a high reluctance magnetic path. Thus, air gap is to be avoided if possible, and yet in the context of this invention, no binding may be allowed to take place which will retard the rapid action of the latch armature 100. By having a larger surface conforming as close as possible to therotating hub of the armature 100, the effective air gap is reduced, or stated otherwise, there is an increased area of air gap. It is desirable to have a dimensionally controlled small air gap which allows high flux flow, and also permits a rugged independent support for the frame 205.

The fundamental operation of the electromagnetic mechanism of FIGURE 1 is essentially the same as that for the mechanism illustrated and described in FIGURE 2. Thus, to stop rotation of the control shaft 71, the coil 194 is energized. This produces a magnetic flux in the core 197 which is coupled to the magnetic portion of the armature 100. When the coil 194 is energized, the lever 100 is attracted towards the pole piece 203, and hence towards the position shown in FIGURE 1, pivoting the lever 100 to the left towards a stop position where it will hook the shoulder 72 of the shaft 71. Conversely, energization of the coil 195 attracts the armature 100 toward the pole piece 204, pivoting the lever 100 in a clockwise direction to its release position.

To illustrate the differences of output nature to which the invention may be employed, the embodiment of FIG- URE 1 provides a spring 220 which lightly urges the armature toward the pole piece 203 at all times. In one use environment, the mechanism controlled by the shaft 71 is dangerous to the operator in the event that power is turned off during the time when the latch is away from the catch shoulder 72. This occurs because should an operator or bystander have their hand in the wrong part of the equipment when the power is restored, immediate operation can begin. Accordingly, by using a light spring 220, whenever power is removed from both coils 194 and 195, the spring will urge the latch into a position to stop the shoulder 72 and prevent machine operation when the current power is restored.

Such use of spring 220 requires that the coil 195 be energized at all times during the operation of the shaft' 71. This is in contradistinction to the output purpose of the FIGURE 2 embodiment wherein a high overpower is provided and then the power immediately shut off. However, the FIGURE 2 embodiment is employed in an environment wherein the output armature may stay in one position for a long period of time, and thus the overpower condition would cause excessive heating. On the contrary, although power is employed in the coil 195 of FIGURE 1 during all times that the latch is open, this period exists for only a moment in time and, therefore, the power condition is acceptable. Furthermore, the light nature of spring 220 is not sufiicient to retard the fast unlatching action of the drive of the armature by power from coil 195.

The two embodiments of the invention both illustrate an output device rockable between open and closed positions, wherein the means for rocking the output device comprises two electromagnets arranged in spaced opposing relationship with an armature positioned between the electromagnets which is shiftable by energization of one of said magnets to a first position and shiftable by the energization of the other of the magnets to a second position. The armature is in intimate magnetic association with an arm of each core at all times, and is shiftable between positions in which it is in contact with one or the other of the pole pieces, but the two electromagnets are electrically energized to alternate the polarization in the magnetic armatures upon each opposite actuation.

Whereas the present invention has been shown and described herein in what is conceived to be the best mode contemplated, it is recognized that departures may be made therefrom within the scope of the invention which is, therefore, not to be limited to the details disclosed herein, but is to be afforded the full scope of the invention as hereinafter claimed.

What is claimed is:

1. A control mechanism capable of rapid intermittent operation comprising: i

a magnetic structure arranged in substantially C-shaped functional configuration including a pair of magnetic cores arranged with ends spaced apart and directed toward each other;

a coil on each of said cores;

a magnetic armature arranged to extend across the open sides of the C of both of said cores, said armature being shiftable between positions in which it is in contact with one or the other of said core ends and remaining in intimate magnetic association with one said core at all times other than during shifting movement;

said coils arranged to generate magnetic fields whose senses are such as to be oppositely directed in relation to the armature and to reverse the direction of induced magnetism in said armature during each shifting movement; whereby a take-off driven element associated with said armature may be driven between limits in a minimum period of time.

2. A control mechanism as defined in claim 1 wherein the C shaped magnetic structures are united in an area extending substantially parallel to the axis of the two coils, and the magnetic armature is seated on the united structures at a midway point directly opposite a midway .point between said cores, with the armature fitted as a knife edge in a notch.

3. A control mechanism capable of rapid intermittent operation comprising a pair of C-shaped magnetic cores arranged with their open sides towards each other and with spaced opposed pole pieces consisting of one arm of each core;

a coil on each of said cores;

a magnetic armature arranged to extend across the open sides of the C of both of said cores, said armature being shiftable between positions in which it is in contact with one or the other of said pole pieces and remaining in intimate magnetic association with one said core at all times other than during shifting movement;

said coils arranged to generate magnetic fields whose senses are such as to be oppositely directed in relation to the armature and to reverse the direction of induced magnetism during each opposite swing; whereby a take-off driven element associated with said armature may be driven between limits in a minimum period of time.

4. A device as set forth in claim 3 in which the portion of the armature in intimate association with both cores is pivotally mounted and has a periphery comprising cylindrical segments, and in which the adjacent arms of the cores are also portions of cylindrical surfaces matched with and minutely spaced from said armature.

5. An electromagnetic actuator capable of driving a work load at optimum operation speed, between a first and second terminal station, comprising:

an armature of magnetically soft alloy;

first and second magnetic coil devices providing opposed terminal positions, said armature having a single working air gap relationship with each coil,

said armature shiftable to reduce said air gap and move to said first station upon energization of said first coil device, said armature shiftable to reduce said air gap and move to said second station upon energization of said second coil device;

said first coil device having a flux path including said armature and only said single working air gap, said flux in said armature having a first polarity direction; and

UNITED STATES PATENTS 286,917 10/1883 Fraser 335-266 952,086 3/1910 Thrasher 335-266 said second coil device having a flux path including said 10 BERNARD GILHEANY Primary Examinerarmature and only said single Working air gap, said G. HARRIS, JR., Assistant Examiner. 

1. A CONTROL MECHANISM CAPABLE OF RAPID INTERMITTENT OPERATION COMPRISING: A MAGNETIC STRUCTURE ARRANGED IN SUBSTANTIALLY C-SHAPED FUNCTIONAL CONFIGURATION INCLUDING A PAIR OF MAGNETIC CORES ARRANGED WITH ENDS SPACED APART AND DIRECTED TOWARD EACH OTHER; A COIL ON EACH OF SAID CORES; A MAGNETIC ARMATURE ARRANGED TO EXTEND ACROSS THE OPEN SIDES OF THE C OF BOTH OF SAID CORES, SAID ARMATURE BEING SHIFTABLE BETWEEN POSITIONS IN WHICH IT IS IN CONTACT WITH ONE OR THE OTHER OF SAID CORE ENDS AND REMAINING IN INTIMATE MAGNETIC ASSOCIATION WITH ONE SAID CORE AT ALL TIMES OTHER THAN DURING SHIFTING MOVEMEANT; 